Behavior of Fuel Droplets in Pulsative Air Flow Through a Model Intake Manifold

A theoretical analysis supplemented by an experimental work was conducted of the behavior of liquid fuel droplets subjected to a pulsative air flow in a T-branched duct of a square cross section for a better understanding of fuel transport process in an intake manifold of an automotive spark ignition engine. The analysis includes the formulation of the simultaneous equations of momentum, heat and mass transfer for computing the locations, temperatures and diameters of moving droplets as a function of spatial coordinates. The results were expressed primarily in terms of the location at the impact deposition of droplets relevant to the formation of liquid film on the bottom wall of the duct. It was revealed that the calculated results agreed well with the empirical data. It was also suggested that the undesirable aspects of liquid film might possibly be relieved if small droplets with high volatility and low density are infused at optimum timing into a warm air flow with a short period of pulsation.